In the conventional art, as a disposable diaper used mainly in an infant and toddler and the like, there is provided a so called open-type disposable diaper provided with a fastening tape for fastening at side flaps of a back waistline unit thereof.
In such an open-type disposable diaper, a structure of a fastening tape is known in which the rigidity of the tip of the fastening tape is lower than the rigidity of the proximal end of the fastening tape (for example, Patent Literature 1). According to a fastening tape with such a structure, even when the wearer of the disposable diaper moves, the tip of the fastening tape easily becomes deformed with following the change in the shape of the body of the wearer, which makes it difficult for the fastening tape to unfasten from the disposable diaper.